Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/chkwon/trafficassignment.jl
Julia package for finding traffic user equilibrium flow
https://github.com/chkwon/trafficassignment.jl
Last synced: 26 days ago
JSON representation
Julia package for finding traffic user equilibrium flow
- Host: GitHub
- URL: https://github.com/chkwon/trafficassignment.jl
- Owner: chkwon
- License: other
- Created: 2015-02-07T17:07:07.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2021-06-03T00:19:35.000Z (over 3 years ago)
- Last Synced: 2024-09-09T05:59:38.337Z (about 2 months ago)
- Language: Julia
- Homepage:
- Size: 651 KB
- Stars: 40
- Watchers: 4
- Forks: 15
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- License: LICENSE.md
Awesome Lists containing this project
README
# TrafficAssignment.jl
[](https://github.com/chkwon/TrafficAssignment.jl/actions?query=workflow%3ACI)
[](https://codecov.io/gh/chkwon/TrafficAssignment.jl)
This package for [the Julia Language](http://www.julialang.org) does basically two tasks: (1) loading a network data and (2) finding a user equilibrium traffic pattern. See [Traffic Assignment](https://en.wikipedia.org/wiki/Route_assignment).
# Install
```julia
julia> Pkg.add("TrafficAssignment")
```
This will install [LightGraphs.jl](https://github.com/JuliaGraphs/LightGraphs.jl) and [Optim.jl](https://github.com/JuliaOpt/Optim.jl), if you don't have them already.
To check if works
```julia
julia> Pkg.test("TrafficAssignment")
```
# load_ta_network
This function loads a network data available in [this TNTP github repository](https://github.com/bstabler/TransportationNetworks). The network name must match with the directory name in the TNTP repository.
Example:
```julia
using TrafficAssignment
ta_data = load_ta_network("SiouxFalls")
# ta_data = load_ta_network("Anaheim")
# ta_data = load_ta_network("Barcelona")
# ta_data = load_ta_network("Winnipeg")
```
The return value is of the TA_Data type, which is defined as
```julia
mutable struct TA_Data
network_name::String
number_of_zones::Int
number_of_nodes::Int
first_thru_node::Int
number_of_links::Int
init_node::Array{Int,1}
term_node::Array{Int,1}
capacity::Array{Float64,1}
link_length::Array{Float64,1}
free_flow_time::Array{Float64,1}
b::Array{Float64,1}
power::Array{Float64,1}
speed_limit::Array{Float64,1}
toll::Array{Float64,1}
link_type::Array{Int64,1}
total_od_flow::Float64
travel_demand::Array{Float64,2}
od_pairs::Array{Tuple{Int64,Int64},1}
toll_factor::Float64
distance_factor::Float64
best_objective::Float64
end
```
# ta_frank_wolfe
This function implements methods to find traffic equilibrium flows: currently, Frank-Wolfe (FW) method, Conjugate FW (CFW) method, and Bi-conjugate FW (BFW) method.
References:
- [Mitradjieva, M., & Lindberg, P. O. (2013). The Stiff Is Moving-Conjugate Direction Frank-Wolfe Methods with Applications to Traffic Assignment. *Transportation Science*, 47(2), 280-293.](http://pubsonline.informs.org/doi/abs/10.1287/trsc.1120.0409)
Example:
```julia
link_flow, link_travel_time, objective = ta_frank_wolfe(ta_data, log="off", tol=1e-2)
```
Available optional arguments:
* method=:fw / :cfw / :bfw (default=:bfw)
* step="exact" / "newton" : exact line search using golden section / a simple Newton-type step (default=:exact)
* log=:on / :off : displays information from each iteration or not (default=:off)
* max_iter_no=*integer value* : maximum number of iterations (default=2000)
* tol=*numeric value* : tolerance for the Average Excess Cost (AEC) (default=1e-3)
For example, one may do:
```julia
ta_data = load_ta_network("SiouxFalls")
link_flow, link_travel_time, objective =
ta_frank_wolfe(ta_data, method=:cfw, max_iter_no=50000, step=:newton, log=:on, tol=1e-5)
```
The total system travel time can be simply computed as
```julia
using LinearAlgebra
system_travel_time = dot(link_travel_time, link_flow)
```
# Contributor
This package is written and maintained by [Changhyun Kwon](http://www.chkwon.net).